How to handle user session failure in Ajax operation

This time I will bring you how to deal with the failure of Ajax operation user session, what are the precautions for Ajax operation user session failure, the following is a practical case, let's take a look.

When using the spingMVC interceptor to handle the problem of user session failure, when the user session fails, a string of javascript strings will be returned to force the user's browser to jump to the login page. However, when Ajax is used to request data, only a string will be responded after the verification fails, and JavaScript will not be executed. This is because the Ajax request is initiated by the XMLHTTPRequest object rather than the browser. After the verification fails, the server returns The information will be received by the XMLHTTPRequest object and saved in the js object.

In order to deal with this situation, Http requests can be judged in the background first, and Ajax requests can be processed separately from ordinary http requests.
Observing the request header information sent by Ajax, we can find that the header information of the Ajax request will contain X-Requested-With:XMLHttpRequest. Through this, we can determine whether it is an Ajax request.

String requestType = request.getHeader("X-Requested-With");
if(requestType != null && "XMLHttpRequest".equalsIgnoreCase(requestType.trim())) {
  //如果是ajax请求
  response.setHeader("sessionStatus", "timeout");
  response.sendError(601, "session timeout.");
  return false;
}

javascript code, you can set the global default options for Ajax requests, once and for all

//设置Ajax请求的全局默认options
jQuery.ajaxSetup({
  type:'post',
  complete:function(xhr, ts){ //XMLHttpRequest, textStatus
    var sessionStatus = xhr.getResponseHeader('sessionstatus');
    if(sessionStatus == 'timeout') {
      alert('页面过期，请重新登录!');
      window.top.location.href = 'Login.htm';
    }
  }
});

The project also uses DataTables to make data tables. I found that the above javascript configuration method does not take effect in datatables. Error messageSee: http://datatables.net/tn/7 You must configure the error attribute of ajax

$('#example').dataTable( {
 "ajax": {
  "url": "findRoles.htm",
  "type": "POST",
  "error": function(xhr, ts, et) { //XMLHttpRequest, textStatus, errorThrown
    var sessionStatus = xhr.getResponseHeader('sessionstatus');
    if(sessionStatus == 'timeout') {
      alert('页面过期，请重新登录!');
      window.top.location.href = 'Login.htm';
    }
  }
 }
});

I believe you have mastered the method after reading the case in this article, and there will be more exciting things Please pay attention to other related articles on php Chinese website!

Recommended reading:

jQuery+Ajax determines whether the entered verification code passes

How to make a smart search box with Ajax Prompt function

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